Metal dispensing tubes have a thin metal diaphragm sealing the dispensing orifice. This metal foil, which was often made integral with the metal tube, is generally known within the trade as a "blind head". Typically, the metal tube will have a closure cap on it, the cap having a pointed means for piercing the blind head in order to dispense the contained product from the tube.
While metal tubes have been used commercially for a long period of time, more recently, attention and interest have been focused on plastic and laminated containers. Plastic and laminated tubes are usually less costly than metal tubes and are less susceptible to chemical attack by certain products. Also, where the user desires to roll up the closed end of the tube, metal tubes tend to fracture with fewer rollings than do the laminated tubes.
Because of these superior performance characteristics of plastic and laminated tubes, these tubes today hold a large share of the tube market. One disadvantage of these tubes, however, is that they typically are closed on the dispensing end only by a plastic screw-on cap. So far as it is known, there is no known use of any hermetic seal on the dispensing end of the plastic or laminated tubes. The lack of a hermetic seal presents a number of problems which depend somewhat on the types of products contained and their sensitivity to the problems presented by this closure. Some products are reactive with gases in the air, such as oxygen, and the normal gaseous infusion noticeably affects product life. Some products desirably packaged in a tube are rather liquidous, and are not adequately contained for longer term storage, such as in commercial inventory, by a closure which is a simple screw-on cap. There is also an increased level of concern regarding malicious tampering with, or contamination of, products which may be ingested, or dispensed on sensitive tissue. Such tampering is easily accomplished with unprotected tube containers by removing the tube cap, doing whatever tampering is contemplated, and then re-emplacing the cap. There is often no way of detecting such tampering.
The problem of sealing an orifice in a bottle-type container for food or pharmaceuticals has been handled by applying a sealant sheet material over the bottle opening before the cap is put on or during cap emplacement. Such sheet materials are sold by the 3M Company of St. Paul, Minn. as product numbers 75M, 456M, and 603. The structures of these products are as follows:
______________________________________ Components 75 M 456 M 603 ______________________________________ White pulpboard .035" None None Wax .00045" None None Aluminum Foil .001 .002" .003" Adhesive negligible thickness Heat Sealable Polyester Film .002" .00045" .002" ______________________________________
These sheet materials are intended to be torn off the bottle and disposed of when the bottle is first opened. When these materials were tested, they were all found too difficult to pierce, and all did significantly impede dispensing of the product, by restricting the functional size of the orifice.
A typical plastic laminated material which is subjected to dead-folding, and is used as the body of a tube sidewall, is disclosed in U.S. Pat. No. 3,505,153 to Haas et al. The tube sidewall is, of course, intended to resist piercing, and therefore this patent is not concerned with a pierceable sealant sheet material.
Another plastic laminated material which is subjected to dead-folding is disclosed in U.S. Pat. No. 3,976,224 to Ericson et al. Again, the disclosed structures are intended to be used as tube sidewalls and are resistant to piercing.
Accordingly, it is an object of this invention to provide a collapsible dispensing tube with a hermetically sealed orifice.
It is a further object of this invention to provide a collapsible dispensing tube having its orifice hermetically sealed with a laminated plastic sheet.
It is also an object of this invention to seal the orifice of such collapsible dispensing tube by a laminated plastic sheet by heat sealing or by the application of radio-frequency heating.
It is a further object of this invention to provide a container with readily pierceable orifice seal wherein the pierced seal does not interfere with dispensing of the product from the container.
It is yet another object of this invention to provide such hermetically sealed containers which are tamper-indicative and which could afford the consumer a ready visual means of detecting if the container contents have been tampered with.
The foregoing and other objects, features and advantages of this invention will be more clearly comprehended from the following detailed description and the accompanying drawings.